Bromiley lives across the street, where she flies the American flag, and is relieved the police chief took down the black and white flag.

“Given what that flag represents, it causes alarm,” Chief Jeffery Cain said. “We are actively investigating, in contact with state and federal authorities and treating the matter very seriously.”

Cain said police are confident they know the person responsible – a man familiar to them.

“At this point, we do have a person of interest,” he said. “We have no information that would indicate any immediate threat to the community.”

Investigators are still determining if a crime was committed.

State Rep. Michael Brewster, R-Pittsfield, who lives near the dam, said he isn't sure. He said he had not been aware the flag was meant to represent ISIS.

“Freedom of speech, I guess. I don't know,” he said.

Residents of the town responded by hanging up American flags around the dam. They also said they are considering some type of patriotic demonstration or celebration in response, and that the incident is not symbolic of their community.